How old were you when you started potty training?

How old were you when you started potty training? My 9 months old but I think it's too early. He won't understand yet. And my mom keeps pushing me, arguing with her about this. She says that then she won't be able to take him out of diapers, he will always be in them. She gives examples from some acquaintances, it annoys me so much. I want to start potty training at a year old, maybe even later. When did you start?